Cleaning apparatus for perforated pipe and the like



` H. c.' YARBROUGH 2,055,55

5 FOR PERFORATED PIPE AND THE LIKE Sept, 29, 93.

CLEANING APPARATU Filed July 5, 1953 2 Sheets-Sheet 1 HAQOLD C.YAQBQOUGH ATTORNEY Sept. 29, 1936. H C YARBROUGH CLEANING APPARATUS FORPERFORATED PIPE AND THE LIKE V Filed July C5, 1935 2 Sheets- Sheet 2 *Ili 93 lNvEN-r'or: HARoLD C. YAQBQoL/GH ATTORNEY Patented Sept. 29, 1936APPARATUS FOR. PERFOBATED THE LIKE CLEANING PIPE AND PATENT .OFFICEHarold C. Yarbrough, Brea., Calif., assignor to 0. P. Yowell Service CoCalifornia Inc., a corporation of Application July 3, 1933, Serial No.678,875

18 Claims. (Cl. 16B-20) This invention has to do in a general way withdevices for cleaning perforated pipe, and is more particularly relatedto a novel type of apparatus which can be used to wash the wallperforations in strainer casings such as are used in the oil producingzone or sand in an oil well.

As is well known to those familiar with the art, during the recession ofthe rock pressure in an oil well, the perforations in the strainercasings tend to become clogged either with sand and sediment, or, in thecase of heavy asphaltic oil they become clogged and caked with asphaltand tar. Several devices have been developed for the purpose of cleaningthese perforations. In my prior Patent No. 1,916,875 issued on July 4,1933, I show a device whereby the perforations are cleaned through the,application of suddensuction to a confined space in the perforated pipe.The present invention, however, relates to a tool operating upon anentirely different principle in that the perforations are washed by theapplication of a pressure fluid derived either from the well or sup-lplied thereto from the surface of the ground.

The use of the tool contemplated by this invention is in itselfsuiiicient to eiect a complete cleaning o'f the perforated pipe undermany conditions, but in some instances it may be found `desirable tofollow its use by that of the tool shown and described 'in my formerapplication referred to above.

In one form of device contemplated by this invention, the pressure fluidis delivered to the tool from the surface of the ground either during orafter its installation in the Well, and may be of a character such aswill react with or dissolve the material which has caked and lodged inthe casing perforations and in the fissures of the formation adjacentthe perforations. This type of tool may also be used in deliveringcement to a confined region in the well'casing'with the idea of stoppingwater leaks, etc.

In another form of my invention, I provide a tool which merely sloshesthe well fluid back and forth through the perforations in a confinedregion of the strainer casing, this tool being effective merely to washthe perforations and the fissures clean of deposited sediment, etc., theforeign material removed by the washing action being carried from thewell after the tool is removed either by means of an ordinary pump bythe flowing action of the well, or by means of a tool such as is shownin my former application referred to above. l

In. the other form of device contemplated by this invention, I provide atool which is similar to that just described in that the uid in the wellis sloshed back and forth in the perforations. but differs from the tooljust described in that part of the liquid withdrawn from the restrictedarea in the perforated casing together with the substance removed fromthe perforations is carried from the well by the tool itself. All'ofthese tools, however, have the common function of washing theperforations by the application of a pressure fluid within a restrictedarea or a confined space in the strainer casing, and in all of the toolscontemplated by this invention such pressure fluid is applied to therestricted area by means of a plunger operating in a working barrel.

The details in the construction of certainpreferred forms of myinvention, together with other objects attending its production, will bebest understood from the following description of the accompanyingdrawings which are chosen for illustrative purposes only, and in which-Fig. 1 is a sectional elevation showing one preferred form of theinvention;

Fig. 2 is a fragmentary section taken in a plane represented by the line2-2 in Fig. 1;

Fig. 3 is a fragmentary section showing the upper end portion of a toolof the type shown in Fig. 1 and illustrating the same as having beenprovided with a special form of fitting whereby the Well iiuid isdelivered into the tool at one point for injection into the strainercasing at another pont;

Fig. 4 is a-sectional elevation showing another modified form of theinvention;

Fig. 5 is a sectional elevation showing still another modiiied form ofthe invention; and

Fig. 6 is a fragmentary sectional elevation showing a portion of thedevice illustrated in Fig. 5 with the parts arranged in a differentworking position from that shown in Fig. 5.

More particularly describing the invention as herein illustrated.reference numeral il (Fig. 1) indicates a perforated pipe or a strainercasing, such as is ordinarily used in oil wells and the like, withinwhich a cleaning device, generally indicated by reference numeral I2, ispositioned. The cleaning device I2, in this form of my invention,constitutes the form referred to above wherein the pressure iiuid isforced into the well, such fluid preferably being placed in the tool atthe time it is installed and being of a nature such that it reacts withor dissolves the material deposited or caked in the perforations of thepipe and in the fissures of the formation.

It is, of course, necessary in a tool of this nature to apply thepressure fluid to a confined region in the strainer pipe, and suchconfined space or region is obtained by means of a pair of packers I3and I3' shown as comprising rubber cups I4 mounted in metal collars I5and retained by wire ribsv I9. The packers are mounted upon a hollowmandrel I1, provided with a closure I8 and a guide shoe I9 at its lowerend, and are held in spaced relation thereon by means of a sleeve 20interposed between the packers.

The collar I5 on the upper packer engages a stop member 2|, welded orotherwise secured to the mandrel. 'I'.l'ie entirey unit, including thepackers and the sleeve, are pressed against the stop member 2| by meansof the shoe I9 which is in threaded engagement with the lower end of themandrel. 'I'he hollow mandrel and the sleeve are provided with openings22 situatedbetween the packers, such openings establishing communicationbetween the interior of the mandrel and the confined space formed by thetwo packers.

The upper open end of the hollow mandrel I1 is mounted in a bushing 23which forms the lower end portion of a working barrel 24. The upper endof the working barrel 24 is mounted in a bushing 25 carried by a sleeve25 which in turn is releasably supported in the strainer casing by meansof a slip mechanism generally indicated by reference numeral 21. Theslip mechanism which may be of 'any conventional type is shown ascomprising a collar 28 having a tapered lower surface 29 engaged byslips 30. The slips in turn are mounted on the upper ends of links 3iwhich in tum are supported by a sliding collar 32 having spring fingers34 in frictional engagement with the interior of the strainer casing.

The lower end of the sliding collar 32 is provided with a bayonet slot36 which receives a pin 31 mounted on the sleeve 26. This arrangement issuch that when the pin 31 is in the notch 36 of the bayonet slot 36, theslips 30 are held inwardly against the inclined face 29 and the entireunit may have an uninterrupted movement into the pipe. When the unit hasreached its predetermined position, the sleeve 26 is rotated by meanswhich will be hereinafter more fully described so as to align the pinwith the straight portion of the bayonet slot whereby further downwardmovement of the unit takes piace relative to the slips which are heldstationary by the frictional engagement of the springs 34 with the wallof the strainer pipe. The slips are, therefore, forced out intoengagement with the interior of the pipe by the tapered surface of thecollar 28 and the unit is locked into position.

The working barrel 24 is provided with a plunger member 39 which may beof any preferred construction but is shown as being a rubber type ofplunger which is'mounted on the lower reduced end portion 40 of ahollow, plunger rod 4I. The plunger rod or-tubing 4I is provided with acollar-42 having recesses 43 adapted to receive lugs 43' in the top ofthe plunger barrel whereby the plunger barrel and the sleeve 26 may berotated at will from the surface of the ground for the purposehereinabove described. The plunger rod 4I extends upwardly through thesleeve 26 and through a packing unit 45 in the collar member 28 and fromthere on in sections to the surface of the ground where it may beoperated in any conventional manner such as by .means of a walking beamor by blocks in the derrick.

The lower end portion of4 the hollow plunger rod is provided with avalve seat indicated at 41 placed in the device as it is lowered intothe well. In other words, after a predetermined number ot sections ofthe hollow plunger tubing have been assembled, the desired quantity ofliquid is poured therein and it is necessary, therefore, to providevalve means in the plunger barrel which will support the weight of thiscolumn of liquid but which will at the same time be released under thepressure action of the plunger to deliver such liquid through the hollowmandrel and the openings into the confined space defined by the packersI3 and I3'. Such a valve is shown in Fig. 1 as comprising what is ineffect an enclosed cage 5I! having a seat 5I in its top, such cage beingmounted in the bottom of the plunger barrel through the threadedconnection 52 and containing a bottom apertured plug 53 which engages aheavy compression spring 54 that presses a ball valve 55 against theseat 5I.

The compression spring 54 is of suiilcient strength to support theweight of a column of liquid in the plunger barrel and the plungertubing of such quantity as may be desired for cleaning the perforationsin the pipe.

In the operation of this device, as pointed out above, the desiredquantity of liquid is poured into the tubing 4I after it has beenlowered into the well to a predetermined depth. The installation of thetool is then continued in the usual manner by lowering the same andadding additional sections to the plunger rod or tubing.

When the unit has reached the desired point at the lower end portion ofthe perforated section, as indicated by the length of the rod which hasbeen lowered into the well, the tubing or plunger rod is rotated therebyreleasing the slips to lock the unit at the desired point. The plungerbarrel having been locked in this manner, the tubing is permitted tomove downwardly of its own weight, thereby forcing the contents of theplunger barrel through the spring-pressed check valve 55 and the hollowmandrel I1 into the coni-ined space and through the perforations of thestrainer casing.

The operation of the plunger may be repeated once or twice for eachsetting if desired, the upward movement of the plunger being effectiveto admit additional. liquid from vthe tubing through the check valve 48into the plunger barrel, suchliquid being forced out into the confinedspacev by the downward movement of the plunger. After one setting hasbeen cleaned, the unit may be raised a distance corresponding to thelength of the space confined by the packers at which time the slips areautomatically reset by permitting the tubing to settle. The unit is thenreoperated in the manner just described. This operation may be repeateduntil the entire length of strainer casing has beenA cleaned.

In the event it is not desired to deliver a foreign material, such as acleaning solvent or an acid into the well, or in the event the wellcontains liquid which can be used to clean the perforations in the pipe,I may provide a device of the class just described with an aperturedcollar 51 (Fig. 3) which is mounted in the tubing 4I at a point abovethe packing 45 in the slip collar r28'. In the use of this device,liquid in the well above the top packer is admitted through ports 58 in.thecollar 61, flowing downwardly through the hollow tubing and beingforced into the well in the manner Just described above.

In order that the packing unit, comprising the two packing members I3and I9', may be lowered downwardly through the casing, I provide suchunit with a by-pass pipe 60 which has its lower end extending throughthe plug I8 opening into the region of the casing below the packing unitand has its upper end extending through the wall of the hollow mandreland opening into the casing above the packing unit( In this manner thedevice may be lowered downwardly through the liquid in the well, suchliquid passing through the by-pass pipe as the unit travels on itsdownward course. i

Referring now to Fig. 4 in which the strainer casing Il' and the slipmechanism I2 are the same as those shown in Fig.41, I show a cleaner ofmodiiied construction which is adapted to merely slosh the liquid of thewell back and Vforth through the perforations in a restricted area ofthe strainer pipe. In this form of my invention I may employ asubstantially solid plunger rod 65 which extends downwardly through thepacking gland into a plunger barrel 66 where it is provided' with asubstantially solid piston 61. This piston is similar to that shown inFig. 1 in that it comprises a rubber or other flexible central portion68 interposed between metal sup-` porting collars or rings 69 and 69'.The interior of the rubber portion 68 is hollowed out to form a chamber10 and this chamber communicates through ports 1| and a bore hole 12with the interior of the working barrel so that the piston receives apressure fluid forcing the same into expanded position during its downstroke.

The lower end portion of the working barrel 66 is secured in a bushing13 which in turn sup- I ports a hollow mandrel 14 similar in all of itsessential respects with the mandrel I1 in Fig. 1. In view of the dualaction, that is, pressure and suction which is applied to the restrictedarea, inf this form of my invention the packing members generallyindicated by reference numerals 15 and 15 are formed so as to withstandboth pressure and suction in that each comprises a pair of oppositelydisposed cups 16 and 11, such cups being mounted on opposite sides of aring 18 which is shown as supporting the reinforcing wires 19 and 80.The uppermost cup 16 engages a stop member 8| on the mandrel. The twosets of cups are held in spaced relation by means of a sleeve 82 likethe construction shown in Fig. 1, and the lowermost set of cups ispressed upwardly against the sleeve by means of a secondary sleeve 83which is in turn engaged by a nut 84 mounted on the lower end of themandrel above the guide shoe i9'.

The packing assembly in this form of my invention, like that shown inFig. 1, is provided with a bypass pipe indicated at 60', and the mandreland spacing sleeve are provided with ports indicated at 22 forestablishing communication between the interior of the hollow mandreland the space confined by the packers. In the operation of this device,the tool is merely lowered into the well in the conventional manner byextending the plunger rod until it reaches the desired point at whichtime the plunger is rotated to release the slip mechanism as describedin Fig. l and the plunger rod is reciprocated much as an ordinary pumpto apply suction and pressure alternately to the coniined space, therebysloshing the liquid out of the well back and forth through theperforations to thoroughly wash them of sediment, etc.

Referring now to Fig. 5, reference numeral Ha indicates ,a strainercasing or a perforated pipe which is shown as containing a modified formof cleaning unit generally indicated by reference numeral 12a. Thiscleaning unit is supported in the casing by means of a slip mechanismgenerally indicated by reference numeral which is the same inconstruction and operation as the slip mechanism described in connectionwith Fig. l.

Reference numerals 9| and 9|' indicate a pair of packers, theperipheries of which engage the interior of the casing, such packersbeing spaced apart to form a confined space S within the perforatedpipe. 'I'he packers 9| and 9| are shown as being of the rubber cup typehaving metal supporting collars 92 and 92'` and reinforcing cages 93 and93'. 'I'he packers are mounted upon a hollow mandrel 94 and are retainedthereon by means of a shoulder 95 formed on the mandrel, a sleeve 96which holds the packers in spaced relation with each other, and a nut 91which is in threaded engagement with the lower end of the mandrel and isshown as being provided with a guide shoe 98.

'Ihe lower end portion of the mandrel is provided with a closure plug99, and the upper end portion of the mandrel is open, being in opencommunication with a bushing |00 which in turn communicates with and issupported by a plunger barrel or working barrel |0|. The hollow mandrelis provided with ports |02 opening into the coniined space S. A

Reference numeral 03 indicates, what I may term, a float-plunger whichis shown as being formed of wood or other suitable material of lowspeciiic gravity having a packing cup |04 on its upper edge engaging theinterior of the working barrel. The iloat-plunger |03 is provided withan upwardly tapered opening |05 which is provided with a valve seat andcage |06 in its upper end `The power cylinder is supported through themedium of a collar and a sleeve I2 from the slip mechanism, generallyindicated at 90. The power piston I0 is mounted on the lower end portionof a plunger tubing or tubular plunger rod I4 which isl provided with acheck valve indicated at H5.

Reference numeral I1 indicates a compression or recoil spring mounted inthe bottom of the plunger barrel or. in the bushing |00 and extending upinto the plunger barrel so as to be engaged by the plunger float when itreaches the bottom of it"s stroke in the manner which will now bedescribed.

In the operation of this device, the tool is lowered into the well tothe desired point at which time the slips are released in the mannerdescribed above to lock the same in place, thereby holding the packingunit so as to provide a conned space in the strainer casing. Meanwhileany liquid which may have entered the `confined space during thedownward movement of the unit or after it is positioned will risethrough the mandrel into the plunger barrel and lift the plunger floatinto the upper end portion of the plunger barrel. As the power plungeris moved downwardly by the weight of the tubing after the unit has beenlocked in place, it creates a substantial vacuum in the operatingcylinder which is released when the power plunger enters the workingbarrel. Such release of pressure is effective to draw additional liquidthrough the strainer casing, or, in the event none has seeped through,to draw'liquid through the perforations fin the strainer casing and intothe working barrel. It will be seen that through this operation theplunger oat will follow the operating plunger to the top of the workingbarrel as the plunger travels upwardly in the operating cylinder. In thedown stroke of the power plunger I I0, however, the weight of the liquidin the hollow plunger rod will hold the check valve .I I closed so thatthe compression of liquid below the power plunger will force the plungerfloat downwardly in the working barrel, thereby expelling liquid fromthe working barrel through the ports |02 and forcing such liquid underpressure through the perforations in the confined space S. In thismanner it will be seen that the operation of this device is to forceliquid under .pressure through the perforations in the confined spaceand then apply sudden suction to the confined space so that liquid isredrawn back through the perforations, thus giving a washing effectsimilar to but possibly more violent than the washing effect obtained bythe washing device shown in Fig. 4.

The spring Ill is provided for the purpose of giving the plunger-floatan initial impelling movement when the pressure thereabove is releasedor, more specifically, when the sudden suction is applied thereto, thuspreventing the possibility of this plunger becoming stuck and permittingall of the liquid to pass up through the check valve without lifting theplunger-float.

It is also possible to extend the spring I I1 a substantial distance upinto the working barrel' and employ a plunger which does not have thelow specific gravity of the plunger-float. In such instance, theoperation of the plunger in the working barrel would be covered entirelyby the spring, the plunger being forced downwardly, compressing thespring while the power plunger was traveling in the operating cylinderand being forced upwardly by the action of the spring when the powerplunger entered the working barrel from the operating cylinder. Fig. 5shows the plungerfloat inthe position which it would occupy under normaloperation when the power plunger is in the top of the operatingcylinder, and Fig. 6 shows the position of the plunger-float just priorto the time at which the power plunger enters the working barrel fromthe operating cylinder.

It will be apparent from the foregoing description that my invention inits three modified forms is capable of applying a pressure fluid to aconfined region within a strainer casing, and it is to be understoodthat, while I have herein described and illustrated certain preferredforms of my invention, the invention is not limited to the preciseconstruction described above, but includes within its scope whateverchanges fairly come within the spirit of the appended claims.

I claim as my invention:

l l. An apparatus for cleaning perforated pipe and the like embodying: apair of packers adapted to engage the interior of said pipe and spacedapart to form a conned space therein; a hollow mandrel supporting saidpackers and having an opening communicating with said confined space; aworking barrel supporting said hollow mandrel and communicatingtherewith; a plunger in said working barrel adapted, during downwardmovement, to force a pressure fluid from said working barrel into saidconfined space; and means for actuating said plunger.

2. An apparatus for cleaning perforated pipe and the like embodying: apair of packers adapted to engage the interior of said pipe and spacedapart to form a confined space therein; a hollow mandrel supporting saidpackers and having an opening (communicating with said conned space; aworking barrel supporting said hollow mandrel and communicatingtherewith; a plunger in said working barrel adapted, during downwardmovement, to force a pressure fluid from said working barrel into saidconned space; a hollow plunger rod for actuating said plunger; and acheck valve between said plunger and said plunger rod for admittingfluid from said` plunger rod to said working barrel during upwardmovement of said plunger.

3. An apparatus for cleaning perforated pipe and the like embodying: apair of packers adapted to engage the interior of said pipe and spacedapart to form a confined space therein; a hollow mandrel supporting saidpackers and having an opening communicating with said confined space;

aworking barrel supporting said hollow mandrel and commimicatingtherewith, a plunger in said working barrel adapted, during downwardmovement, to force a pressure fluid from said working barrel into saidconfined space; and means -for actuating said plunger, said plungerbeing space; a working barrel supporting said hollow mandrel andcommunicating therewith; a plung er in said working barrel adapted,during downward movement, to force a pressure fluid into said confinedspace; and means for actuating said plunger, said plunger comprising afloat, packing means on said float engaging the interior of said workingbarrel, and a check valve in said float adapted to close under theapplication of pressure from the top portion of said working barrel.

5. An apparatus for cleaning perforated pipe and the like embodying: apair of packers adapted to engage the interior of said pipe and spacedapart to form a confined space therein; a. hollow mandrel supportingsaid packers and having an opening communicating with said confinedspace; a. working barrel supporting said hollow mandrel andcommunicating therewith; a plunger in said working barrel adapted,during downward movement, to force a pressure fluid from said workingbarrel into said confined space;

means for actuating said plunger; and a by-pass conduit communicatingbetween the regions of said pipe on either side of said confined space.

6. An apparatus for cleaning perforated pipe y and the like embodying: aworking barrel; means for releasably supporting said Working barrel insaid pipe; a valve seat in the bottom of said working barrel; a checkvalve engaging the underside of said valve seat; a compression springnormally holding said check valve against its seat; a plunger member insaid working barrel; a downwardly opening check valve in said plunger; ahollow plunger rod for actuating said plunger; a hollow mandrel mountedon the bottom of said working Vinder; a `working valve in said powerplunger;

barrel; and a pair of packers mounted on said mandrel and engaging saidpipe to form a confined space therein, said hollow mandrel beingprovided with' an opening communicating with said confined space. l

7. An apparatus for cleaning perforated pipe and the like embodying: aworking barrel; means for releasably supporting said working barrel insaid pipe; a downwardly opening check valve in the bottom of saidworking barrel; a hollow mandrel communicating with said working barrel'through said check valve; a pair of packers mounted on said mandrel toform a confined space in said pipe, the wall of said mandrel beingprovided with an opening communicating with said coniined space; aplunger member in said working barrel; a tubular plunger rod foractuating said plunger; and a downwardly opening spring-pressed checkvalve in said tubular plunger rod.

8. An apparatus for cleaning perforated pipe and the like embodying: aworking barrel; means for releasably supporting said working barrel insaid pipe; a valve seat in the bottom of said working barrel; a checkvalve engaging the underside of said valve seat; a compression springnormally holding said check valve against its seat; a plunger member insaid working barrel; a downwardly opening check valve in said plunger; ahollow plunger rod for actuating said plunger; a hollow mandrel mountedon the bottom of said working barrel; and a pair of packers mounted onsaid mandrel and engaging said pipe to form a confined space therein,said hollow mandrel being provided with an opening communicating withsaid confined space, said compression spring being of suiicient strengthto maintain said working barrel check valve closed against the pressureof a substantial column of fluid in said working barrel and said hollowplunger rod.

9. An apparatus for cleaning perforated pipe and the like embodying: aworking barrel; means for supporting said working barrel in said pipe; asubstantially solid plunger in said working barrel; a plunger rod foractuating said plunger; a hollow mandrel secured to the bottom of saidworking barrel in open communication therewith; and a pair of packingmembers mounted on said mandrel and adapted to engage said pipe to forma confined space therein, the wall of said hollow mandrel being providedwith an opening communicating with said confined space.

10. An apparatus for cleaning perforated pipe and the like embodying: aworking barrel; means for supporting said working barrel in said pipe; asubstantially solid plunger in said working barrel; a plunger rod foractuating said plunger; a hollow mandrel secured to the bottom of saidworking barrel in open communication therewith; and a pair of packingmembers mounted on said mandrel and adapted to engage said pipe to forma confined space therein, each of said packing members comprising a pairof oppositely disposed cups, the wall of said hollow mandrel beingprovided with an opening communicating with said confined space.

11. Anapparatus for cleaning perforated pipe and the like embodying: aworking barrel; an operating cylinder of smaller diameter than saidworking barrel mounted on the top of said working barrel in opencommunication therewith; a

i plunger-float in said working barrel, said plunger-float having apassage therethrough; a downwardly closing check valve in saidplunger-naat passage; a power plunger in saidoperating cylmeans foroperating said power plunger; a hollow mandrel mounted on the bottom ofsaid working barrel in open communication therewith; and a pair ofpackers mounted on said l mandrel adapted to engage the interior of saidpipe and spaced apart to form a coniined space therein, said hollowmandrel having an opening in its wall communicating with said confinedspace.

l2. An apparatus for cleaning perforated pipe and the like embodying: aworking barrel; an operating' cylinder of smaller diameter than saidworking barrel mounted on the top of said working barrel in opencommunication therewith; a plunger-fioat in said working barrel, saidplunger-iioat having a passage therethrough; a downwardly closing checkvalve in said plunger-neat passage; a recoil spring mounted in thebottom of said working barrel and adapted to be engaged by saidplunger-float; a power plunger in said operating cylinder; a workingvalve in said power plunger; means for operating said power plunger; ahollow mandrel mounted on the bottom of said working barrel incommunication therewith; and

' a pair of packers mounted on said mandrel adapted to engage theinterior of said pipe and spaced apart to form a confined space therein,said hollow mandrel having an opening in its wall communicating withsaid confined space.

13. An apparatus for cleaning the perforations in perforated pipeembodying: a pair of packers adapted to engage the interior of said pipeand spaced apart to form a confined space therein; means forintermittently applying pressure to said confined space comprising ahollow mandrel supporting said packers and having one open end andanother opening communicating with said confined space;`a working barrelcommunicating with the open end of said mandrel; a plunger in saidplunger barrel; means for operating said plunger; and a check valve atthe open end of said mandrel adapted to be opened under pressure fromsaid plunger.

14. An apparatus for cleaning the perforations in perforated pipeembodying: a pair of packers adapted to engage the interior of said pipeand spaced apart to form a confined space therein; and means foralternately applying pressure and suction to said conned spacecomprising a hollow mandrel supporting said packers, said mandrel havingone open end and having an opening in its wall communicating with saidconfined space, a working barrel communicating with the open end of saidmandrel, a substantially solid plunger in said working barrel, and meansfor actuating said plunger.

l5. An apparatus for cleaning the perforations in perforated pipeembodying: a pair of packers adapted to engage the interior of said pipeand spaced apart to form a confined space therein; and means foralternately applying pressure and suction to said confined spacecomprising a hollow mandrel supporting said packers, said mandrel havingone open end and having an opening in its wall communicating with saidconfined space. a working barrel communicating with the open end of saidmandrel, a plunger-float in said working barrel, a power cylinder ofsmaller diameter than said working barrel mounted on the top of saidworking barrel, a pistn in said power cylinder, means for moving saidpiston through said power cylinder into said working barrel, saidplunger-float having a passage therethrough, and a check valve in saidpassage adapted to close under the action of pressure from said vnicating with said hollow mandrel and a plunger in said working barrelfor intermittently applying pressure to said coniined space.

17. An apparatus for cleaning perforated pipe and the like embodying:packing means adapted to engage the interior of said pipe and form aconfined space therein; -a hollow mandrel supporting said packing meansand having open communication with said confined space; a working barrelcommunicating with said hollow mandrel; a plunger in said working barreladapted to force pressure uid from said working barrel through saidmandrel into said coniined space during relative movement between saidplunger and said working barrel in one direction; and means foreffecting relative movement between said plunger and said workingbarrel.

18. An apparatus for cleaning perforated pipe and the like embodying:packing means adapted to engage the interior of said pipe and form aconfined space therein; a hollow mandrel supporting said packing meansand having open communication with said confined space; a working barrelcommunicating with said hollow mandrel; a plunger in said working barreladapted to alternately apply pressure and suction in said coniined spaceduring relative movement between said plunger and said working barrel inopposite directions; and means for effecting rel'- ative movementbetween said plunger and said working barrel.

HAROLD C. YARBROUGH.

